:host {
    display: block;
    position: relative;
    box-sizing: border-box;
    width: 280px;
    height: 12px;
    background: url();

    .color-alpha-slider__bar {
        position: relative;
        background: linear-gradient(to right,
                rgba(255, 69, 0, 0) 0%,
                rgb(255, 69, 0) 100%);
        height: 100%;
    }

    .color-alpha-slider__thumb {
        position: absolute;
        cursor: pointer;
        box-sizing: border-box;
        left: 189px;
        top: 0;
        width: 4px;
        height: 100%;
        border-radius: 1px;
        background: #fff;
        border: 1px solid #f0f0f0;
        box-shadow: 0 0 2px rgba(0, 0, 0, 0.6);
        z-index: 1;
    }
}